Medication Summary
Until cultures are available, the choice of antimicrobial agents should be directed toward the most commonly involved pathogens. Regimens using beta-lactam/beta-lactamase inhibitor combinations, carbapenems, or second-generation cephalosporins with anaerobic coverage are excellent empiric choices for the coverage of enteric bacilli and anaerobes. Metronidazole or clindamycin should be added for the coverage of Bacteroides fragilis if other employed antibiotics offer no anaerobic coverage.
Amebic abscess should be treated with metronidazole, which will be curative in 90% of cases. Metronidazole should be initiated before serologic test results are available. Patients who do not respond to metronidazole should receive chloroquine alone or in combination with emetine or dehydroemetine.
Systemic antifungal agents should be initiated if fungal abscess is suspected and after the abscess has been drained percutaneously or surgically. Initial therapy for fungal abscess is currently amphotericin B. Lipid formulations may offer some benefit in that the complexing of drug to lipid moieties allows for concentration in hepatocytes. Further investigation is required for definitive proof. Cases of successful fluconazole treatment after amphotericin failure have been reported; however, its use as an initial agent is still being studied.
Ultimately, the organisms isolated and antibiotic sensitivities should guide the final choice of antimicrobials.
Duration of treatment has always been debated. Short courses (2 wk) of therapy after percutaneous drainage have been successful in a small series of patients; however, most series have reported recurrence of abscess even after more prolonged courses. Currently 4-6 weeks of therapy is recommended for solitary lesions that have been adequately drained. Multiple abscesses are more problematic and can require up to 12 weeks of therapy. Both the clinical and radiographic progress of the patient should guide the length of therapy.
Antibiotics
Class Summary
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Meropenem (Merrem)
Bactericidal broad-spectrum carbapenem antibiotic that inhibits cell-wall synthesis. Effective against most gram-positive and gram-negative bacteria.
Has slightly increased activity against gram negatives and slightly decreased activity against staphylococci and streptococci species compared to imipenem.
Imipenem and cilastatin (Primaxin)
For treatment of multiple organism infections in which other agents do not have wide-spectrum coverage or are contraindicated due to potential for toxicity.
Cefuroxime (Ceftin)
Second-generation cephalosporin maintains gram-positive activity that first-generation cephalosporins have; adds activity against Proteus mirabilis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, and Moraxella catarrhalis. Condition of patient, severity of infection, and susceptibility of microorganism determine proper dose and route of administration.
Cefotetan (Cefotan)
Second-generation cephalosporin indicated for infections caused by susceptible gram-positive cocci and gram-negative rods.
Dosage and route of administration depends on condition of patient, severity of infection, and susceptibility of causative organism.
Cefoxitin (Mefoxin)
Second-generation cephalosporin indicated for gram-positive cocci and gram-negative rod infections. Infections caused by cephalosporin-resistant or penicillin-resistant gram-negative bacteria may respond to cefoxitin.
Cefaclor (Ceclor)
Second-generation cephalosporin indicated for infections caused by susceptible gram-positive cocci and gram-negative rods.
Determine proper dosage and route based on condition of patient, severity of infection, and susceptibility of causative organism.
Clindamycin (Cleocin)
Lincosamide for treatment of serious skin and soft tissue staphylococcal infections. Also effective against aerobic and anaerobic streptococci (except enterococci). Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes causing RNA-dependent protein synthesis to arrest.
Metronidazole (Flagyl)
Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. Used in combination with other antimicrobial agents (except for Clostridium difficile enterocolitis).
Antifungal agents
Class Summary
Their mechanism of action may involve an alteration of RNA and DNA metabolism or an intracellular accumulation of peroxide that is toxic to the fungal cell.
Amphotericin B (AmBisome)
Produced by a strain of Streptomyces nodosus; can be fungistatic or fungicidal. Binds to sterols, such as ergosterol, in the fungal-cell membrane, causing intracellular components to leak with subsequent fungal-cell death.
Fluconazole (Diflucan)
Synthetic oral antifungal (broad-spectrum bistriazole) that selectively inhibits fungal cytochrome P-450 and sterol C-14 alpha-demethylation.
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Table 1: Presenting symptoms and signs in 715 patients diagnosed with liver abscess.
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Table 2: Microbiologic results from 312 cases of liver abscess compiled from the literature.
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Table 3: Comparison of the radiologic procedures used in the diagnosis of liver abscess.
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Table 4: Underlying etiology of 1086 cases of liver abscess compiled from the literature.
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Computed tomography (CT) scan findings of liver abscess are shown. A large, septated abscess of the right hepatic lobe is revealed. Abscess was successfully treated with percutaneous drainage and antimicrobial therapy.
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Computed tomography (CT) scan findings of liver abscess are shown. A large anterior abscess involving the left hepatic lobe is revealed. Abscess was successfully treated with percutaneous drainage and antimicrobial therapy.
